Android选择框怎么实现分组功能

要实现 Android 选择框的分组功能，可以使用 ExpandableListView 控件来展示分组列表，并在每个分组下面展示可选择的子项。

首先，在布局文件中添加 ExpandableListView 控件：

<ExpandableListView
    android:id="@+id/expandableListView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

然后，创建一个适配器类来管理分组和子项的数据，并绑定到 ExpandableListView 控件上：

public class MyExpandableListAdapter extends BaseExpandableListAdapter {
    
    private Context context;
    private List<String> groups;
    private Map<String, List<String>> items;

    public MyExpandableListAdapter(Context context, List<String> groups, Map<String, List<String>> items) {
        this.context = context;
        this.groups = groups;
        this.items = items;
    }

    @Override
    public int getGroupCount() {
        return groups.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return items.get(groups.get(groupPosition)).size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return groups.get(groupPosition);
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return items.get(groups.get(groupPosition)).get(childPosition);
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        // Implement how to display group view
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        // Implement how to display child view
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    // Other required methods
}

在 getGroupView 和 getChildView 方法中实现如何展示分组和子项的视图。

最后，在 Activity 或 Fragment 中设置 ExpandableListView 控件和适配器：

ExpandableListView expandableListView = findViewById(R.id.expandableListView);
List<String> groups = new ArrayList<>();
groups.add("Group 1");
groups.add("Group 2");

Map<String, List<String>> items = new HashMap<>();
List<String> group1Items = new ArrayList<>();
group1Items.add("Item 1");
group1Items.add("Item 2");
items.put("Group 1", group1Items);

List<String> group2Items = new ArrayList<>();
group2Items.add("Item A");
group2Items.add("Item B");
items.put("Group 2", group2Items);

MyExpandableListAdapter adapter = new MyExpandableListAdapter(this, groups, items);
expandableListView.setAdapter(adapter);

这样就可以实现一个具有分组功能的选择框。

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